Pakistan Veterinary Journal 01/2004;
Source: DOAJ

ABSTRACT A six-week trial was conducted to study the effect of decreasing dietary crude protein (CP) level on the performance of broilers in hot climatic conditions. Four experimental rations having CP 23 (control group), 22, 21 and 20%, with optimal amino acid balance were prepared. All the four rations were isocaloric having ME 3200 kcal/kg with Energy: Protein (E:P) 139.0, 146.5, 152.4 and 160 in diets A, B, C and D respectively. One hundred and twenty day-old chicks were randomly distributed into 12 experimental units, each having 10 chicks. Rations were randomly allotted to experimental units such that each unit received three replicates. The experimental diets were fed to birds from day 1st to 42nd. Performance of birds was monitored in terms of weight gain, feed consumption and feed conversion ratio (FCR). At the end of experiment, two birds per each replicate were randomly selected and slaughtered to record the data on carcass yield, breast meat yield, abdominal fat and composition of breast meat. Results of the trial suggested that weight gain was significantly (P<0.01) increased in birds on diets with CP 20 and 21%. Feed consumption and FCR remained un-changed for all the treatment groups. Eviscerated carcass yield was significantly (P<0.05) higher for the group fed on diet with 20% CP. Breast meat yield, abdominal fat and composition of breast meat also remained un-changed. Economic evaluation of the trial revealed that decreasing CP levels from 23 to 20% resulted in reduced feed cost per kg of live weight gain, which clearly indicated that this approach was useful especially in severe summer conditions. The overall picture of the study suggests that dietary protein level of broilers could be reduced from 23 to 20%, with beneficial effects on growth performance and carcass characteristics and increased economic returns in hot environmental conditions, provided that levels of essential amino acids are closely looked after.

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    ABSTRACT: The experiment was conducted to evaluate the effect of varying dietary metabolizable energy (ME) and crude protein (CP) concentrations on broiler performance during hot summer conditions. One day old straight-run (0.50 male and 0.50 female) Starbro broiler chicks (n = 600) were randomly divided into 30 experimental units of 20 chicks each. Two levels of dietary ME (12.13 and 12.55 MJ/kg) and three levels of dietary CP (190, 210 and 230 g/kg) were used in a 2×3 factorial arrangement giving six dietary treatments. Level of essential amino acids were maintained in all the diets by supplementing low CP diets with crystalline amino acids. Each of the experimental diets was offered to five replicates from hatching to 28 d of age. At the end of the experiment, two birds from each replicate were randomly selected for data on dressing yield, breast meat yield, abdominal fat, and liver and gizzard weights. Increasing dietary ME significantly increased the BW gain, abdominal fat and liver weights, and protein and fat contents of the carcass whereas the dry matter of carcasswas reduced by increasing dietary ME. Dietary CP had quadratic effects on BW gain, F:G, carcass weight, and dry matter and protein contents of the meat. Breast weight and fat contents of meat increased linearly with increasing CP of the diets. The low CP diets (i.e., 190 g/kg) at high ME (i.e., 12.55 MJ/kg) increased the BW gain, feed intake, carcass weight and improved F:G. However, lowest F:G was observed in birds fed 210 g CP and 12.13 MJ ME/kg of diet. Protein and fat contents of the carcass were increased in birds fed on diets having high CP and ME whereas dry matter contents of meat improved with high CP and low ME diets. The results of the trial showed a correlation between dietary CP and ME and hence the optimal value for one cannot be predicted without considering the other. Briefly, low CP with high ME diets improved the overall performance when environmental temperature ranged from 32 to 39 ◦C.
    Animal Feed Science and Technology 10/2008; 146:302-312. DOI:10.1016/j.anifeedsci.2008.01.006 · 2.09 Impact Factor
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    ABSTRACT: In this study, a total of 11000 Ross-308 broiler chicks, in 4 groups (2750 chicks) eachwere fed on mash or pellet diet from the 1 to 28 day of age to compare their performance according to different diet. The chicken st th groups were reared on deep litter in open poultry farm at about 2450 meter altitude above sea. The chicks were fed on Mash from koudijus (Gr. 1), Pellet from koudijus (Gr.2), Pellet from Hendrix N.V. (Gr.3) and Pellet from Hendrix N.V Merksem (Gr.4). The results showed that feeding on Pelleted ration improved the weightgain, feed intake and feed /gain compared to mash diets. The highest body weight throughout all of the4 weeks wasobserved in Pellet fromHendrix fed chickens (1103.73gm), while the lowestbody weight in different weeks were observed inMash from Koudijus. During the whole period it was observed that pelleting increased the feed intake compared to mash feed. The highest (1595g/bird) at 4 week and the lowest (1474g /bird/week) feed th consumption were observed in pellet Hendrix (gr 4) and Mash Koudijus (gr1); respectively. The highest (0.786) FCR value was observed in mash group, which indicated lowfeed conversion efficiency.The mashfeed given only for the first four weekssignificantly reduced the subsequent incidence of ascites. The mortality with ascites in birds receiving pelleted feed wasconsistentlythe greatestand was the lowest in birds fed on mash.
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    ABSTRACT: A trial was conducted to study the effect of lowering dietary crude protein (CP) with optimal amino acids profile on growth and whole body composition of broilers from 1 to 26 days of age. Four isocaloric (Metabolisable energy - 2925 kcal y kg) experimental broiler diets with CP levels of 23 (control), 22, 21 and 20% were formulated. Digestible lysine was maintained at 1.1% of the diet. A total of 1,760 dayold, Hubbard broiler chicks were randomly divided into 16 experimental units of 110 chicks and each diet was offered to 4 experimental units at random. Weight gain, feed intake and feed conversion ratio were not significantly affected by any of the treatment groups during the experimental period. Whole body composition and protein utilisation of broilers were also unaffected by the reduction in dietary CP content. However, total protein intake was decreased (P < 001) and protein efficiency ratio was increased (P < 001) linearly with low CP diets. Economics of different experimental diets fed to birds revealed that maximum economic returns were observed in 20% CP diet. The results suggested that dietary CP level could be reduced to 20% during starter period without any harmful effect on broiler performance when supplemented with critical amino acids.
    Avian biology research 06/2008; 1(1):19-25. DOI:10.3184/175815508X336639 · 0.90 Impact Factor

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